You could measure the current in each radial with a clamp on RF ammeter.
Especially useful if the original currents were measured. This might
separate damaged from ok radials although for my 8 radial elevated
system new, there was a 3:1 variance in currents due to what each radial
was near/over. My sum of radial currents did equal the vertical element
current which showed the feedline was well enough choked.
I used an MFJ-843 meter which works even with a poor clamp on the
ferrite core sensing element. It is not well calibrated so bench cal
with a dummy load and transmitter at various power levels on the
frequency of use is important if accurate current values are needed.
There are also lots of DIY designs, but the MFJ has an amplifier for the
low amperage you might find with large numbers of radials at a TX power
level you are comfortable with.
Grant KZ1W
On 12/2/2022 08:01, Jorge Diez - CX6VM wrote:
OK thanks Paul
how can you measure that a radial system is still good over the years?
Maybe the cable is degraded, or is cutted in some points if animals are
around.
Is any easy way to determine that the radial system on a vertical antenna
is still good?
thanks!
Jorge
CX6VM/CW5W
El vie, 2 dic 2022 a las 12:06, Paul Christensen (<w9ac@arrl.net>) escribió:
Jorge,
N6LF's material is based largely on measured results in support of
theory.
Paul, W9AC
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of Jorge
Diez - CX6VM
Sent: Friday, December 2, 2022 9:57 AM
To: Paul Christensen <w9ac@arrl.net>
Cc: Ignacy Misztal <no9e@arrl.net>; tower and HF Antenna Construction
Topics. <towertalk@contesting.com>
Subject: Re: [TowerTalk] 16om vertical and the number of radials
I think Paul wants to know the "real" situation, not theory. He want to
know if the theory is 100% in accordance with real big stations with many
radials on the antennas
73,
Jorge
CX6VM/CW5W
El vie, 2 dic 2022 a las 11:50, Paul Christensen (<w9ac@arrl.net>)
escribió:
Ignacy,
There's a lot of published information that addresses your question.
Some material is rooted in commercial applications and even more in
the amateur literature where modeling is compared with measured results.
As a starting point, I would carefully read Rudy Stevens' material:
https://www.antennasbyn6lf.com/design_of_radial_ground_systems/
Paul, W9AC
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of Ignacy
Misztal
Sent: Friday, December 2, 2022 9:25 AM
To: tower and HF Antenna Construction Topics.
<towertalk@contesting.com>
Subject: [TowerTalk] 16om vertical and the number of radials
Do more radials on a 160m vertical bring more improvements than shown
by simulation?
Most simulations show that going above 32 radials on 160m brings
minimal improvement, say 1 db to 2 max. Even for low angle signals.
On the other hand, some really loud stations n 160m, say 5-10 db above
the crowd, use a massive amount of radials. This is for inland
stations, far away from salt water.
Is there any discrepancy between modeling and real life performance
with the number of radials? Does adding radials beyond 32 help much?
Any real stories?
Ignacy NO9E
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--
73,
Jorge
CX6VM/CW5W
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